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authorPeter Zijlstra <peterz@infradead.org>2021-05-25 10:25:19 +0300
committerPeter Zijlstra <peterz@infradead.org>2021-06-01 17:00:08 +0300
commitec6aba3d2be1ed75b3f4c894bb64a36d40db1f55 (patch)
tree0fd56814090efcd59ce2f2b29906043853764b23 /kernel
parent9ce4d216fe8b581e4da4406461a4cfc9acbfa679 (diff)
downloadlinux-ec6aba3d2be1ed75b3f4c894bb64a36d40db1f55.tar.xz
kprobes: Remove kprobe::fault_handler
The reason for kprobe::fault_handler(), as given by their comment: * We come here because instructions in the pre/post * handler caused the page_fault, this could happen * if handler tries to access user space by * copy_from_user(), get_user() etc. Let the * user-specified handler try to fix it first. Is just plain bad. Those other handlers are ran from non-preemptible context and had better use _nofault() functions. Also, there is no upstream usage of this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lore.kernel.org/r/20210525073213.561116662@infradead.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c19
1 files changed, 0 insertions, 19 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 745f08fdd7a6..e41385afe79d 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1183,23 +1183,6 @@ static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
}
NOKPROBE_SYMBOL(aggr_post_handler);
-static int aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
- int trapnr)
-{
- struct kprobe *cur = __this_cpu_read(kprobe_instance);
-
- /*
- * if we faulted "during" the execution of a user specified
- * probe handler, invoke just that probe's fault handler
- */
- if (cur && cur->fault_handler) {
- if (cur->fault_handler(cur, regs, trapnr))
- return 1;
- }
- return 0;
-}
-NOKPROBE_SYMBOL(aggr_fault_handler);
-
/* Walks the list and increments nmissed count for multiprobe case */
void kprobes_inc_nmissed_count(struct kprobe *p)
{
@@ -1330,7 +1313,6 @@ static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
ap->addr = p->addr;
ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
ap->pre_handler = aggr_pre_handler;
- ap->fault_handler = aggr_fault_handler;
/* We don't care the kprobe which has gone. */
if (p->post_handler && !kprobe_gone(p))
ap->post_handler = aggr_post_handler;
@@ -2014,7 +1996,6 @@ int register_kretprobe(struct kretprobe *rp)
rp->kp.pre_handler = pre_handler_kretprobe;
rp->kp.post_handler = NULL;
- rp->kp.fault_handler = NULL;
/* Pre-allocate memory for max kretprobe instances */
if (rp->maxactive <= 0) {